Printing telegraph apparatus



Dec. 10, 1940. H. LoTTl-:RMANN PRINTING TELEGRAPH APPARATUS Filed June5, 1958 s sheets-sheet 1 nl. .w mN n nN 3A M R E U O L N A M R E HGttomeg Dec. l0, 1940.

FIG. 2

PRINTNG TELEGRAPH APPARATUS H. LOTTERMANN Filed June 3, 1938 3Sheets-Sheet 2 -HERMAN LOTTERMANN Gttorneg Dec. 10, 1940. H. LOTTERMANN2,224,546

PRINTING TELEGRAPH APPARATUS Y VFiled June 3. 1958 3 Sheets-Sheet 3 FIG.3

INVENTOR. HERMAN LOTTERMANN AT ORNEY.

Patented Dec. 10, 1940 I narran stares PRHNTHNG TELEGRAPH APPARATUSHerman Lottermann, Qhicago, Ill., assigner to 'Eeletype Corporation,Chicago, El., a corporation of Delaware Application June 3, 1938, SerialNo. 211,496

l Claim.

This invention relates to printing telegraph apparatus and particularlyto printing telegraph apparatus in which the characters are printed -inpage form from type elements carried upon the periphery of a rotatableand selectively arrestable type wheel.

An object of the invention resides in the provision, in a printingtelegraph receiving unit embodying a type wheel which is readilyremovable for adjustment or replacement, of instrumentalities fordetermining the correct angular position of the type wheel with respectto its supporting shaft.

The invention features an arrangement whereby one type wheel may beremoved and another substituted therefor with complete assurance ofproper alignment. v

In Patent No. 2,130,360 granted November 21, 1939, to Howard L. Krum etal., there is disclosed a type wheel printer with reference to Vwhichthe present invention stands as an improvement. According to thedisclosure of that application, a type wheel having its hub integraltherewith is slidably supported upon a type wheel shaft which carries astop arm that is engageable with any selected one of a pluralityT ofstop pins controlled by a code disc selector mechanism. At the upper endof the type wheel shaft, there is removably secured a horizontallyextending arm which has at its free end a depending arm which enters aslot in the periphery of the type Wheel. Rotation is imparted to thetype Wheel by the horizontally extending arm with the depending portion,and the type wheel is permitted to move axially of the shaft by asliding of the slot in the periphery upon the depending portion of thetype wheel driving arm. When it becomes necessary to remove the typewheel from the shaft, such as for adjustment, repair, or replacement, it

is necessary to remove the driving arm at the upper end of the shaftafter which the type Wheel and its hub may be lifted from the shaft. Itwill be observed that removal of the type Wheel necessitates removal ofits driving connection and,

unless care is exercised when the apparatus is reassembled to the typewheel shaft, misalignment of the type wheel with respect to the shaftmay result.

According to the present invention, rotation of the type wheel isimparted by the type wheel shaft to a hub from which the type wheel isseparable, so that the type wheel may be removed from the shaft withoutdisturbing the driving connection and without altering the angularposition of the hub with respect to the shaft. The

(ci. la7-5s) type wheel is secured to the hub by screws, the heads ciwhich are readily accessible from the top of the type wheel, and whichextend through a central disc portion of the type wheel and threadedlyengage the hub. The disc portion 5 of the type wheel has secured theretoa locating pin which extends downwardly from the underside of the typewheel. The upper part of the type wheel hub is provided with a slotwhich the locating pin of the type wheel enters when the l@ type wheelis seated upon the hub. It is thus impossible to assemble the type wheelto the hub in any other than the correct angular position with respectto the type wheel shaft.

Certain features of invention disclosed Vbut not la claimed herein arealso disclosed and are claimed in copending application Serial No.193,642 led March 3, 1938, by Albert H. Reiber; Serial No. 203,021 ledApril 20, 1938, by Berthel F. Madsen; Serial No. 204,038 led April 25,1938, by Carl 20 A. Levin; Serial No. 208,761 filed May 19,1938, byEdward S. Larson; and Serial No. 210,816 filed May 31, 1938, by Carl W.Swan.

For a com-plete understanding of the invention, reference may be had tothe following detailed 25 description to be interpreted in the light ofthe accompanying drawings, wherein Fig. 1 is a perspective view of thecombined transmitting and receiving mechanism according to the presentinvention, certain portions being 30 broken away to clarify the showing;

Fig. 2 is a front elevational view of the receiving and printingmechanism; and y Fig. 3 is an exploded perspective view of the typewheel mounting and driving mechanism. 35

Referring now to the drawings and particularly to Fig. 1, the referencenumerals I6 and Il designate generally the typing unit and keyboardtransmitter unit, respectively, of a printing telegraph apparatusembodying the present inven- 40 tion. lThe keyboard transmitter unit llis generally similar to the transmitter disclosed in copendingapplication Serial No. 77,796, led May 4, 1936, by Albert H. Reiber, andtyping unit i6 embodies improvements on the typing unit dis- 45 closedin the copending application.

The foundation of the keyboard transmitter unit is the base casting I8to the forward Vertical wall of which is secured a slotted comb i9.

A plurality of key levers 2l are pivoted within 5@ the casting i3 forrocking movement in a vertical plane, and these key levers protrude fromthe interior of base I8 through a slot in comb i9. The key levers 2l areprovided with key tops 22 and are arranged to impartl characteristicset- `tings to permutation code bars contained within base I8 as fullydisclosed in Patent No. 1,595,472 granted August 10, 1926, to Howard L.Krum. To the code bars are articulated lock levers 23 pivotallysupported intermediate their ends and projecting above the upper surfaceof base casting I8 through apertures therein. The lock levers 23 aretherefore subject to permutative setting by the code bars under thecontrol of key levers 2 I The upwardly projecting portions of the locklevers 23 are disposed between brackets 24 and 26 secured to base I8,and aligned with each of the lock levers 23 is a contact controllinglever 21, the levers 21 being pivotally supported by a pivot rod (notshown) extending between brackets 24 `and 26. A transmitting contactspring 28 individual to each of the levers 21 is mounted betweeninsulating strips upon laterally extending portions of br-ackets 24 and26, as indicated at 29. The upper end of each contact spring 28 engagesa gooseneck portion of lever 21 and the flexing of contact spring 28into and out of engagement with a shorter associated contact spring iscontrolled by gooseneck lever 21. The' rocking of the gooseneck lever 21is, in turn, controlled by the lock levers through blocking lugs (notshown) a lever 21 being unblocked when its corresponding lock lever ispresented in extreme clockwise position and being blocked when itscorresponding lock lever is in extreme counterclockwise position.

Bracket 24 and another bracket designated by the reference numeral 3|rotatably support a signal transmitting distributor shaft 32. Near oneend shaft 32 has secured thereto a gear 33 to which rotation iscontinuously imparted by ari-'- other gear as will presently appear.Adjacent to gear 33, shaft 32 has secured thereto the driving element 34of a jaw clutch. A driven clutch element 36, slidable upon shaft 32, iskeyed to a cam sleeve 31 and is urged toward clutch driving element 34by a compression spring 38. A pivoted clutch throwout lever 39 normallyholds driven clutch element 36 out of engagement with driving element 34against the force exerted by compression spring 38. Clutch throwoutlever 39 has an arm 4I which terminates substantially in engagement withan abutment screw 42 carried by a clutch tripping bell crank 43. Adepending arm 44 of bell crank 43 has its outer end disposed in the pathof a lug 46 carried by a link 41 which enters the keyboard base I8 andis there connected to a universal bail (not shown). When link 41 isshifted forwardly of the keyboard transmitter base by operation of theuniversal bail under the control of one of the key levers 2l, ity rocksbell crank 43 clockwise which, in turn, trips clutch throwout lever 39and permits spring 38 to shift driven clutch element 36 into engagementwith driving element 34. forward, it is cammed downwardly by cooperationof a cam projection 48 with the head of a screw 49 carried by aforwardly'extending portion of bracket 26. The camming of link 41downwardly permits the free end of arm 44 of bell crank 43 to escapefrom lug 46 so that -bell crank 43 may vreturn immediately to itsextreme counterclockwise position and permit clutch throwout lever 39 toreturn immediately into position for arresting the clutch comprisingelements 34 and 36 at the conclusion of one revolution thereof, eventhough a key lever should be held depressed and link 41 retained in itsforward position for a prolonged interval of time. Thus As link 41 ismoved.

the operation of cam sleeve 31 by the jaw clutch is confined to singlerevolution in response to each operation of a key lever. A tensionspring 5I maintains engagement between cam projection 48 of link 41 andthe head of screw 49.

The cam sleeve 31 carries a lock bail operating cam 52 and a pluralityof impulse timing cams 53. Cam 52 controls the operation of a lock bail54 pivotally supported by brackets 24 and 26, lowering the bail intoblocking relation to the lock levers 23 as the cam sleeve 31 begins torotate, and lifting it at the end of a cycle. The function of the lockbail 54 is to prevent the shifting of lock levers 23 during a cycle ofrotation of the impulse timing cams 53 and thus prevent mutilation of asignal combination established by the depression of a key lever 2|. Eachof the cams 53 is aligned with one of the transmitting contact controllevers 21 and is engaged by a portion of the aligned lever. Each of thecams 53 has a. notch 56 in the periphery thereof which, when presentedto the associated transmitting contact control lever 21, releases thatlever for rocking movement in counterclockwise direction, and the lever21 rocks unless restrained by its associated lock lever 23. The recesses56 in the several cams 53 are arranged spirally about the cam assemblyso that the levers 21 are released for rocking movement successively.When a lever 21 is permitted to rock counterclockwise by its cam 33, itscontact spring 21 iiexes into engagement with the associated shortcontact spring and a current impulse is impressed upon the telegraphline, the duration of which corresponds to the interval in which thelever 21 remains in its counterclockwise position. The cams 53 thusvdistribute to the telegraph line the signal impulses corresponding to acharacter represented by a key lever depressed. One of the contactcontrolling levers 21 has no lock lever associated with it and operatesinvariably once in each cycle of operation of the transmitting cam forimpressing on the line the 'stop impulse.

The principal foundation element of the typing or receiving unit is acasting which mounts on the keyboard base I8 and has a portion 6Ilocated centrally of the base I8 and a portion 62 extending transverselyof the base I8 in proximity to the rear edge thereof. Thumb screws areemployed for securing the casting comprising portions 6I and 62 to thebase I8, one of those screwsv being indicated at 63. A secondary casting64 extends transversely of the keyboard base I8 and is secured toportion 62 of the primary casting by any desired means, such as screws.The primary casting supports all of the power driven shafts, theoperating cam assemblies, the selector mechanism, the printingmechanism, and the ribbon feed mechanism. The secondary casting 64supports the platen carriage vand associated mechanism, the signalbells, and a set of levers by which various functions are performed.

The primary selector mechanism which integrates the signal combinationsgenerated in the keyboard transmitter mechanism, hereinbefore described,or in a remote transmitter, is indicated generally by the referencenumeral 66 and is generally similar to the primary selector mechanismdisclosed in the hereinbefore identified c0- pendlng application ofAlbert H. Reiber, Serial No. 77,796. The principal elements of theselector mechanism 66 are a selector cam assembly 61, a selector magnet68, and a sword and T-lever assembly 69, the last mentioned assembly aswell as the selector magnet being supported by a mounting plate 1|carried by the forwardly extending portion 6| of the primary casting.The selector cam assembly 61 is carried by the upper end of a verticallypositioned shaft which is rotatably supported in bearing blocks 12 and1,3. The selector cam assembly 61 has flanges 14 secured thereto atopposite ends, and in spaced relation to each ange 14 is a flange 16secured to the shaft which supports the cam assembly 61. A friction disc11 occupies the space between each of the flanges 14 and the adjacentflange 16. Considerable friction is generated between the discs 11 andthose positioned on either side of them so that selector cam assembly 61will rotate with its supporting shaft except when restrained under thecontrol of selector magnet 63, as is Well known in this type of singlemagnet selector mechanism.

Just above the point at which it enters lower bearing block 12, theshaft has secured thereto a gear 18. An electric motor (not shown)drives a pinion which meshes with gear 18 so that the shaft to which thegear-18 is secured is continuously rotated. It may be added at thispoint that a gear 19 carried by a stub shaft meshes with gear 18 andthat a spiral gear 8| also secured to the stub shaft meshes with gear 33carried by the transmitter shaft 32. Thus rotation is imparted to thetransmitting distributor shaft 32 from the motor pinion through gears18, 19, 8| and 33.

The sword and T-lever mechanism 69 is actuated under the joint controlof selector cam assembly and the selector magnet 68 to interpret orintegrate a series of impulses representing a signal combinationpreparatory to setting T- levers S2 in accordance with the signalcombination. Each of the T-levers 82 .engages one arm of a transfer bellcrank 83, the other arm of which is articulated to one of the notchedcode discs of a code disc selector mechanism indicated generally by thereference numeral 86.

The code disc selector mechanism 84 has a circular arrangement ofvertically positioned stop pins 85 which project through slots in thetopmost plate of the mechanism Stop pins 86 are biased inwardly radiallyof the code disc selector mechanism and near their upper ends they restagainst the edges of shiftable notched code discs as is fully disclosedin the copending application of Albert H. Reiber, Serial No. 77,796. Thenotching of the code discs is such that for any permutative setting ofthe discs under the control of T-levers S2 one only of the stop pins 36nds presented to it an alignment of notches, whereupon the pin thereforenters the alignment of notches under the influence of its biasing-spring, its upper end moving inwardly. A type wheel stop arm S1 clampedto type wheel shaft 88 is of such length that in revolving, it justclears those of the stop pins 86 which are held in their outermostpositions by the code discs, but finds blocking its path any pin 36which has entered an alignment of notches in the periphery of the codediscs. The type wheel shaft 88 extends downwardly through the code discselector mechanism B coaXially thereof and receives a continuous torquefrom the driving motor through any convenient means, such as a gearcarried by the shaft 88 and connected thereto by friction discs, thegear being continuously in mesh with the motor pinion. With thisarrangement, the shaft 88 is always prepared to rotate and is free to doso when any stop pin 3S which had been previously selected is moved outof the path of the stop arm 81 upon the resetting of the code discs.With this arrangement, shaft 88 may be arrested in any angular positionin which stop arm 81 encounters a stop pin 86.

The setting of the T-levers 82 according to the operation of the swordlever mechanism 69 is controlled by a transfer bail 9| which is camoperated as will presently appear.` Transfer bail 9| is pivotallysupported by an upper mounting screw 92 and by a lower mounting screwwhich does not appear in Fig. l. Transfer bail 9| is biased incounterclockwise direction by tension spring 93 and has oppositelyextending arms 94 and 96, the former of which is only partiallyindicated in Fig. 1 but which supports transfer springs, as is clearlyindicated in the copending application Serial No, 77,796, and the latterof which carries a locking blade 91 that cooperates with extensions 98of T-levers 82. Locking blade 91 ordinarily blocks the extensions 98 ofT-levers 82 whether they be presented in extreme clockwise orcounterclockwise position. The rocking of transfer bail 9| in clockwisedirection to effect the resetting of T-levers 82 is accompanied bywithdrawal of locking blade 91 out of the path of movement of T-leverextensions 98. the transfer has been completed, .transfer bail 9|returns to its extreme counterclockwise posi- `tion and locking blade 91is restored to locking position with respect to extensions 98.

The front portion 6| of the primary foundation casting for the typingunit has secured thereto spaced brackets and |02. A shaft |03- isrotatably supported in vertical position between brackets |0| and |02.Shaft |03 has secured thereto near the lower end a gear |04 whichpermanently meshes with a gear |06 supported by gear 18 and securedthereto by any desired means, such as screws. The hub of gear |04 hassecured thereto the driving portion |01 of a positive engagement clutchmechanism, the driven portion of which is indicated by the referencenumeral 08, The driven element |08 may be of the type disclosed incopending application Serial No. 165,437, filed September 24, 1937, byB, F. Madsen, having in its periphery a groove designated |02 in thepresent application, which receives the portion HH of the clutchthrowout lever l2. The portion il l of the clutch throwout lever l2confines driven clutch element E08 tosubstantially complete engagementwith driving element |91 during a cycle of operation following thetripping of the clutch, and prevents acceleration of the driven elementof the clutch from the speed imparted to it by the driving element |01,should any torque generated by negative load resulting from theinteraction of a cam follower and its cam be applied to the drivenclutch element |08. Driven clutch element |08 is slidably splined orkeyed'to a cam assembly sleeve ||3 and is urged into engagement withdriving element |01 by compression spring I4.

Clutch throwout lever H2 is carried by the lower end of a pivoted bailH6, the upper pivot of which is indicated H1. At its upper end, bail H6is provided with an arm H5, the free end of which is disposed in thepath of the lowermost cam projection |20 of selector cam assembly 61.Bail H6 is biased in counterclockwise direction by tension spring |2|.When cam projection |20 on selector cam assembly B1 encounters arm H ofbail l S, the bail is rocked in clockwise direction, thus withdrawingclutch throwout lever i l2 from restraining engagement with the drivenclutch element 08 of the clutch on the front shaft, and permittingdriven element |06 to move into engagement with driving element |01whereby rotation is imparted to cam sleeve |I3.

Cam sleeve I I3 supports three cams designated ||8, IIS, and |25. CamI|9 is engaged by a follower roll |22 carried by an arm |23 secured totransfer bail 9|. The direction of rotation of cam sleeve ||3 iscounterclockwise and cam |I9, in being rotated, imparts clockwiserotation to arm |23 and therefore to transfer bail 9|. Transfer bail 9|,as previously set forth, effects the permutational rearrangement ofT-levers 82 and therefore the notched code discs in the code discselector mechanism 84 in accordance with a signal combination which hasbeen integrated in the sword lever mechanism 69.

As previously set forth, there is a shaft rotatably supported invertical position by bearing blocks 12 and 13 to which the gear 18 issecured. Below bearing block 13 the shafty has secured thereto thedriving element |24 of a positive drive clutch, the'driven element ofwhich is indicated |29. Driven element |29 isslidably splined or keyedto a main cam assembly |30- and is urged into engagement with drivingelement |24 by a compression spring |26. 'The engagement anddisengagement of the elements |24 and |29 of the mainv cam assemblydriving clutch mechanism is controlled by a pivoted clutch throwoutlever |21'to which is secured an arm |28 that extends forwardly of thetyping unit and terminates in the path of the apex of cam ||8 carried bycam sleeve |I3 on the front shaft. As indicated in Fig. 1,-in which theclutch mechanism on the shaft and on the maincam driving shaft are;shown in their rest positions, the rest position of the apex of` cam ||8is a small angular distance in counterclockwise direction from the endof arm |28 which effects the tripping of the main cam clutch comprisingelements |24 and |29. Since, as previously stated, cam cylinder ||3rotates in counterclockwise direction, it will be apparent that cam ||8operates upon arm |28 to effect the tripping of driven clutch element|29 just before cam ||8 reaches the end of a cycle of operation.

The bracket |0| which rotatably supports the upper end of shaft |03pivotally supports a bail ISI, the pivot being indicated |32. The bail|3| supports a cam follower arm which has been omitted from the showingof Fig. 1 for the reason that it would conceal substantial portions ofthe main cam assembly |30 carried by the rotatable shaft which issupported in bearing blocks 12 and 13. The cam follower arm car'- riesat its free end a follower roll which engages cam |25 at a point betweencam assemblies ||3 and |24. The contour of cam |25 comprises a smoothgradual rise and a sharp drop-oif, the drop-off beingindicated by areference numeral |33. As cam |25 rotates counterclockwise, it shiftsits follower roll away from the axis of shaft 03 and thus imparts acounterclockwise. rotation to bail |3I. In the rest position of cam |25,the drop-off |33 is a small angular distance beyond the point ofengagement of the cam follower roll with cam |25. The tendency of thecam |25 therefore is to permit bail |3| to return sharply to its extremeclockwise position just before cam |25 reaches its rest position.However, as will presently appear, a cam included in the cam assembly|30 assumes control of bail |3| just before the sharp drop-off |33 incam |25 is presented to its follower, and the cam in cam assembly |30holds bail |3| in extreme counterclockwise position for a predeterminedinterval and thereafter controls the restoration of bail |3I to itsextreme clockwise position.

Bail |3| has integral therewith an arm |34 which extends toward the rearof the typing unit and` terminates in a spring hanger hook |36. Hook |36supports one end of a tension spring |31, the opposite end of which isconnected to agis arm |38 of a type wheel supporting frame Frame |39 isprovided with a vertically disposed slot I4I, through which extends astud |42 supported by a portion of the frame of the typing unit. At thetop, frame |39 has a horizontally extending portion |43 through whichtype wheel shaft 88 passes and in. which is rotatably held the hub of atype wheel |44. Vertically disposed guide pins |46, only one of whichappears in Fig. 1, are supported by a stationary bracket |41 at the topof the typing unit and pass through ,lapertures' in the `horizontalportion |43 of type wheel supporting frame I39. The pins |46 and thecooperating elements' comprising slot |4| and stud |42 permitoscillatory movement of frame |39 vertically, and guide the frame inthat move-l ment. Frame |39 is provided with an abutment screw |48against which arm |34 of'bail |3| rests when thebail |3I is in extremeclockwise p0- sition and frame |39 is in the lowermost position. Whenbail |3| is rocked in counterclockwise direction by cam |25, bail arm|34 tends to move out of engagement with abutment screw |48 and spring|31 tends to be distended. Spring |31, in turn, lifts frame |39, andthus type wheel |44, the normal position of which is below the printingline, is elevated so as to bring character elements carried upon theperiphery of the type wheel into position to effect printing in lineupon a page carried in engagementwith cylindrical platen` |49. When bail|3| is restored to its extreme clockwise positionl. arm |34 engagesabutment screw |48 and restores frame |39 to its lowermost positionwhich, in turn, restores type wheel |44 to its-lowermost position,whereby each character becomes visible immediately after being printed.

As previously set forth, main" cam sleeve |30 is set in operation by thetripping of clutch throwout lever |21 by cam |I8 included in front camassembly ||3 just before cam ||8 reaches its rest position. Theuppermost of the cams carried by cam assembly |30, designated |5|, isengaged on the periphery thereof by a follower roll |52 carried at theend of a lever |53 which is pivoted at |54. Lever |53 has integraltherewith an arm |56 which is provided near its outer end with aplurality of spring connection apertures |51. Any one of the apertures|51 is adapted to receive one end of a tension spring |58, the other endof which is supported by a spring post |59. Spring |58 biases lever |53in counterclockwise direction, thus urging cam follower roll |52 intoengagement with the periphery 0f cam |5|. The several spring mountingapertures |51 in arm |56 of lever |53 are at different distances fromspring post |59 so that the tension exerted by spring |58 and thereforethe torque applied to lever |53 may be varied.

A print hammer operating bail |6| is pivotally supported by pivot |54and coaxially mounted pivot |62. At its lower end, bail |6| is providedwith an arm |63 which supports adjustable abutment screw |64 and alsoone end of a tension spring |66. The inner end of abutment screw |64engages an ann |61 of lever |53 and the rearmost end of tension spring|66 is also connected to arm |61 of lever |53. With this arrangement,bail |6| tends to occupy an extreme clockwise position with respect tolever |53, the extremity of the position being determined by abutmentscrew |66.

Print hammer operating bail |6| has integral therewith at its upper enda lever arm |68. At its free end, lever arm |68 is loosely articulatedto a print hammer |69. Print hammer |69 eX- tends between ribbon spools|1I, rotatably mounted upon a ribbon feed mechanism supporting plate|12. Print hammer |69 is provided with upper and lower arms |13 and |14,respectively, which are disposed in the same vertical plane. Lower arm|14 enters a slot in a bracket |16, carried by ribbon feed mechanismfoundation plate |12, and by means of slotted bracket |16, print hammer|69 is held in a ver- .ticai plane and is guided in recprocatory mo,-

tion imparted by arm |68 of bail |6l. 'I'he upper arm .|13 of printhammer |69 is longer than the lower arm |16 and extends across theperiphery of type wheel |49 and cross the upper end of type wheel shaft88. At its free end, arm |13 is provided with a depending portion |11which, in turn, is provided with an arm |18, the location of which is inalignment with the foremost portion of platen |49, which portion is atthe level whereprinting occurs. Print hammer |69 is provided in itslower edge with a shallow recess 18, the base of which rests upon andslides upon a retainer bar |15 secured to ribbon mechanism base plate|12. The motion of print hammer |69 to eect printing is limited byengagement of Vone end of recess |16 with bar |15, and the restorationalmotion may, if desired, be limited by engagement of the other end ofrecess |10 with bar |15.

The print hammer |69may -be lifted out of its position above the typewheel |46 to permit adjusting or changing the type wheel, by springingthe free end of print bail arm upwardly until the rearrnost end ofrecess |10 clears bar |15, whereupon arm |141 of the print hammer may bedrawn clear or' slotted bracket |16, and the print hammer may be rotatedupwardly in a vertical plane about its pivot of articulation with bailarm |68.

Type wheel |69 may be generally similar to the type wheel disclosed inthe hereinbefore identied application of Albert H. Reiber, Serial No.77,796, and also in Patent No. 2,180,360|- granted November 21, 1939, toHoward L. Krum et ai. As shown in the application and in the patent andas clearly indicated in Fig. l of the present application, type wheel|64 is provided with a plurality of radially disposed type pallets |19which are reciprocably mounted in radial slots in type wheel IM, and areprovided at their outer ends with type elements |8|. There may be twosuperposed rows of type pallets |19, and by means of the lifting of typewheel supporting frame |39 by lever |36, either of the rows of typepallets may be brought into alignment with rearwardly presented portion|18 of print hammer |69. For any angular position of arrestment of typewheel |66 by the cooperation of type wheel stop arm 81 with a selectedstop pin 86, two of the type pallets |19 will be directed toward platen|69 in the same vertical plane as print hammer |69. According to thedistance that type wheel |44 has been lifted by lever arm |36, thedistance being controllable, as will appear later, one or the other ofthe type pallets |19 will be disposed directly in the path of portion|18 of print hammer |69.

Cam |5l, in its normal or rest position, holds print bail operatinglever |53 in extreme clockwise position in opposition to the tension o!spring |58. Spring |66 holds print hammer bail |6| in extreme clockwiseposition with its abutment screw |64 in engagement with arm |61 of printbail operating lever |53. Thus, print hammer |69 is held .in retractedposition. At a predetermined time in the operation of cam |5I, a sharpdrop-oli is presented to follower roll |52 of printing bail operatinglever |53. When the drop-oi is encountered, lever |53 is rocked sharplyin counterclockwise direction by spring |58. Lever |53 impartscounterclockwise movef ment to bail |6| through abutment screw |64. Theangular distance through which lever |53 rocks, as cam follower |52descends to the lowest or innermost point on the periphery of cam |5| isjust short ofsuiicient to drive print hammer |69 .positively against thetype pallet |19 aligned therewith. However, the inertia of bail |6| andprint hammer |69 causes spring |66 to yield and abutment screw |64 tomove out of engagement with arm |61. Thus print hammer |69 overtravelsor moves a greater distance than it would if vpositively interconnectedwith lever |53, the overtravel being caused by the inertia of bail |6|and print hammer |69, and being permitted by spring |66.

As soon as the energy generated by the inertia of bail |6| and printhammer |69 has been expended, spring |66 withdraws print hammer |69 inthe direction of its retracted position until abutment screw |66 returnsinto engagement with arm |61 of lever |53. The remainder of the movementof print hammer |69 to its rest position is eiected by the restorationof lever |53 to its extreme clockwise position by cam |5I. Theovertravel in the movement of print hammer |69 is sufficient toreciprocate the aligned type pallet |19 radially of type wheel |99 toeffect printing. During the period of overtravel and restoration, thefree end of arm |13 of print hammer |69 is presented between the typepallets adjacent to that which is being operated, so that the type wheel|96 could not be rotated, even if permitted to do so by arm 61, due tothe fact that interference between arm |13 of print hammer |69 andadjacent unoperated type pallets would occur. Spring |66 withdraws printhammer |69 from a position of interference with unoperated type palletsmuch more rapidly than it could be withdrawn if positively connected toprint hammer bail operating lever |53. Thus, with the arrangementhereinbefore described, the print hammer |69 is projected and retractedin the shortest possible interval of time so that more time may beallowed for the rotation of type wheel |66 to the position correspondingto the next selection.

In a preceding paragraph, the lifting of the type wheel to bring eitherof its two rows of type pallets into printing position was described.The

lifting is accomplished by the counterclockwise rocking of bail |3|which has an arm |34 interconnected with the type wheel supporting frame|39 by spring |31. It was stated that the lifting of the type wheelsupporting frame |39 is effected by a cam |25 on the front shaft. It wasalso stated that the lowering of type wheel supporting frame |39 iscontrolled by a cam included in the cam assembly |36 on the v` mainshaft. This cam is indicated by the reference numeral |88, and is of theinternal species having its cam surface on the inside of a dependingperipheral flange. The internal cam surface is engaged by a followerroller carried at the free end of A,an arm |81, secured to type wheellifting bail |3|. Spring |31 biases bail |3| in clockwise direction aspreviously set forth and, in so doing, urges the follower roller carriedby arm |81 to seek engagement with the internal cam surface of cam |86.Cam |86 does not have a restricting channel, so that the followercarried by arm |81 is free to be moved away from engagement with theinterior of the depending flange 'of cam |86 when bail |3| is rocked incounterclockwise direction by cam |25. During the initial stages of thelifting of frame |39 by cam |25, cam |86 may be stationary.

About the time that cam has rocked bail |3| to its extremecounterclockwise position, and before the drop-oil of the camv ispresented to its follower roller, the innermost portion of the camsurface of cam |86 is presented inv engagement with the follower rollercarried by cam follower arm |81. During the engagement of the followerroller carried b y arm |81 with whatever dwell there may be vat theinnermost portion of the internal cam surface of cam |86, bail l|3| willbe held in extreme counterclockwise position and lever arm |34 'will beheld in a corresponding'p'osition. -As cam |86 continues to rotate andthe receding cam surface is presented to `its follower (the recessionbeing radially away from the axis of the cam)`,.bail |3| be restored bya lcontrolled motion to its extreme clockwise position, and type wheelsupporting frame |39 will be restored to its lowermost position ".torender visible the character just previously printed. It-will beapparent that when the type wheel frame |39 is being elevated,

the cam follower. by means of which the loweringr of the frame willsubsequently be controlled, is moved out of engagement with its camsurface, and that when the frame |39 is being held in elevated position.and is being lowered, the cam follower bv which its elevation wasaccomplished Awill be held out of engagement with the elevating cam. v

Of the principal mechanisms of the typing unit I6. there remains forconsideration only the function mechanism. This mechanism is, ingeneral. similar in construction and operation to the function mechanismdisclosed in the copending application of Albert H. Reiber, Serial No.77,796. The function mechanism may be understood to include thosemechanisms by which such operations as shift, unshift, carriage return,line feed, signal bell operation, and transmitter disablement areselected and accomplished. Those functions which are materiallydifferent from the corresponding functions, as disclosed in thecopending application of Albert H. Reiber, Serial No. 77,796. and whichwill be described in detail, are shift and unshift, by means of whichselection of characters in the letters or figures bank of type palletsis accomplished.

'Ihe selection of a function is accomplished by means of a testingmechanism which is camcontrolled. Since the testing operation can beconveniently performed by a. groove or channel cam, a channel 9| isprovided in the upper surface of print bail operating cam |5|. A camfollower which could not be shown in Fig. l, is fitted into the grooveor channel |9| in cam |5I, and the follower arm is part of a bail |92which is operated to test for the selection of functions, and tocondition in accordance with the selection'one or more of a plurality offunction bars, indicated generally by the reference numeral |93. Themanner in which the presence of a function is tested and in which thefunction bars |93 are conditioned is fully disclosedin the copendingapplication of Albert H. Reiber, Serial No."1'1,796.

The function bars |93 are pivotally mounted upon rod |94. Rod |94 issupported between spaced arms |96 and |91, which comprise a functionbail pivoted upon pivot rod |98. The lower arm |91 of the functionbail-has integral therewith an arm |99 at the free end of which issupported a cam follower roller 20|. A function cam 202, carried by themain cam sleeve |30, has its periphery engaged by roller 20 I, and whencam 202 occupies rest position, arm |99 and the function bail comprisingarms |96 and |91 are disposed in extreme clockwise position.

At their free ends, the arms |96 and |91 support a spring post .203 to`'which is hooked one end of yeach of a plurality of tension springs204. Each of the springs 204 has its other end connected to one of thefunctionbars |93. Thus, the function bars |93 are biased incounterclockwise direction, and movement of`any of them in clockwisedirection is opposed lby its particular tension spring204.

'I'he conditioning of lfunction bars |93, under the control of bail |92in response to a function selection, is manifested by rotation of one ormore of the function bars.|93 through a small angular distance inclockwise direction. Such rotational movement brings the conditionedfunction bar' out of alignment with the unselected function bars andAinto position to initiate or perform its assigned function. Y after theconditioning of one of the function bars |93, cam 202 rocks its followerarm 20| and the function bail comprising arms |96 and |91 incounterclockwise direction. Since the function bars |93 are pivotallymounted upon rod |94, carried by bail arms |96 and 91, they are movedendwise toward the rear of the printer as cam follower roller 20| ismoved to its outermost position with respect to cam 202. Those of thefunction bars |98 whichl have not been conditioned by being rocked inclockwise direction are reciprocated idly while one conditioned functionbar |93 initiates or performs the assigned function as a result of thereciprocatory movement. The rod |94, carried by function bail arms |96and |91, also is pivotally engaged by a spacing pawl 206 which isreciprocated to effect spacing of the platen carriage as the functionbars |93 are reciprocated rearwardly of the printer. Thespacing'operation and the performance oi' the several functionsexcepting shift and unshif-t are sumciently similar to those disclosedin the copending application Serial No. 77,796, that it is consideredunnecessary to describe them in detail here. However, the shift andunshift functions will now be described.

The hereinbefore identified stud |42, which guides the type wheelsupporting frame |39 in its upward and downward movements, .extendsthrough a horizontally extending slot in a slide member 201. The slidemember 201 is also provided with an open ended slot 208 through whichextends a screw 209, carried by the frame of the typing unit. The stud|42 and screw 209 support the slide member 201 and guide it throughout aImmediately limited sliding movement forwardly andrearwardly of thetyping unit.

The slide member 201 has integral therewith a. vertically extending arm2| The arm 2| is 5 provided near its upper end with a step cut aperture2|2. By virtue of the step cutting, two abutments or stop surfaces areprovided, the lower of which is indicated by the reference numeral 2|3,and the upper of which is indicated 2M and is the upper end of theaperture 2|2. The Atype wheel supporting and lifting frame |39 hasadjustably secured thereto a. bracket 2|6, which has an arm 2|1,extending into the aperture 2|2 of the slide member 201. When the typewheel lifting frame |30 is lifted by bail arm |34, operating throughspring |31, arm 2|1 of bracket 2|6 may encounter either of the stopsurfaces 2|3 or 2M, depending upon whether the slide member 201 ispresented in its rearmost or foremost position, and thereby the typewheel lifting frame |39 will be arrested in either of two positions ofelevation while bail arm |34 continues to be rocked to its extremecounterclockwise position. When the type wheel lifting frame |39 isarrested by the lower stop surface 2|3 of slide member 201 the upper rowof type pallets carried by type wheel |99 is presented in alignment withthe operating extension |18 of print hammer |69, and when the frame |39is permitted to be lifted until its arm 2|1 encounters the uppermoststop surface 2m, the lower row of type pallets will be presented inalignment with the print hammer |69,and with the character impressionlevel of the platen |29. The movement of slide member 201 from one ofthe other of its two positions is accomplished by two levers pivotedupon stud |92,one of the levers being pivotally supported between slidemember 201 and the frame elements which support stud |42 and which,therefore, is behind slide 40 member 291 and cannot be seen in Fig. l,and the other of which is pivotally supported between slide member 201and type wheel lifting frame |39 and is indicated by the referencenumeral 2|8 in Fig. l. A screw 2|9 establishes a pivotal in- 45terconnection between the slide member 201 and its operating lever 2 8.Lever 2 8 is provided with a depending finger 22|. The first and secondof the function bars |93, counting from the top, each have extendinglaterally therefrom a 50 lug, one of which appears in Fig. 1 and it isindicated by the reference numeral 222. The depending finger 22|, oflever 2|8, occupies a posi- 'tion directly in the path of lug 222 whenthe function bar which carries lug 222 has been con- 55 ditioned forfunction performance by being rocked in clockwise direction preparatoryto being moved endwise by cam 202, operating through arm 20| and bailarms |96 and |91. When lever 2|8 is in its extreme counterclockwiseposition, which is 60 the condition when slide member 201 occupies therearmost of its possible positions, finger 22| is disposed substantiallyat the limitv of movement of lug 222 so that it will not be affected ifthe function bar by which lug 222 is carried is 65 conditioned andreciprocated. When, however,

the slide member 201 occupies the foremost position, lever 2 i8 will bepresented in extreme clockwise position and its depending finger 22|will be positioned to be engaged by lug 222, early in the 70 cycle ofmovement of that lug rearwardly of the typing unit. Under theseconditions counterclockwise movement of lever 2|8 by lug 222, as itmoves rearwardly of the typing unit, will result in rearward movement ofslide member 201 which 75 is articulated to lever 2|8 by screw 2|9,whereby slide member -201 will be shifted to its rearmost position withstop surface 2|3 in the path of arm 2|1 carried by type wheel liftingframe |39. It will be understood that the timing of the apparatus issuch that type wheel supporting frame |39 is held lowered by bail arm|34 when slide member 201 is shifted so that there shall be nointerference between arm 2|1 and the step-cut portion of aperture 2|2during the movement of slide member 201.

The restoration of the slide member 201 to its forward position isaccomplished by the lever which corresponds to lever 2|8 and which ispivoted between slide member 201 and the frame member which supportsstud |22 so thaty it does not appear in Fig. 1. .A screw 223 establishesa pivotal connection between this lever and the slide member 201. 'I'hispivotal interconnection is above stud |92 so that when the lever isrocked in counterclockwise direction, the slide member 201 will be movedforwardly of the typing unit to its foremost position. The lower end ofthe lever which is pivoted to slide member 201 at 223 may be similar tothe lower end of lever 2|8 so that when it is in extreme clockwiseposition, it will be disposed in the path of the laterally extendingprojection of that one of the function bars |93, the function of whichis to shift the slide member 201 to its foremost position to permit thetype wheel lifting frame |39 and the type wheel |24 to be lifted totheir uppermost position whereby printing may be effected from the lowerrow of type pallets.

It will be apparent from the foregoing description of the levers whichcontrol the shifting of slide member 201 that both of these leverseffect control by being rocked in counterclockwise direction, one beingoperative to shift the slide member 201 rearwardly and the other beingoperative to shift it forwardly. It will also be apparent that as eitheris rocked in counterclockwise direction by its assigned function bar|93, the motion which it imparts to the slide member 291 will cause theother lever to be rocked in clockwise direction so that they will bepresented alternately in position to be operated by their respectivefunction bars.

In addition to operating the function levers |93 and the spacing pawl206, 'the function bail also operates a ribbon feed lever 226. Thislever is pivoted upon a stud 221 Xed to a stationary portion of thetyping unit and its lower end engages the arms |96 and |91 of thefunction bail. At its upper end, lever 226 is articulated to a link 228which has a slot in which is disposed one end of a ribbon feed lever229. The ribbon feed mechanism Which is operated by lever 229 may be 4substantially identical with that disclosed in the copending applicationof Albert H. Reiber, Serial No. 77,796. The ribbon feed mechanismsupporting plate |12 supports pairs of vertically disposed pins 23|which serve as guides for the inked ribbon 232, and there is also asemicircular ribbon guide which is supported by the type wheel liftingframe |39 in spaced relation to the type wheel |94 between the typewheel and the platen |99. Thus, the ribbon guide 233 is lifted each timethe type wheel |69 is lifted, and a port-ion of the ribbon 232 is alwayspositioned between the type wheel |49 and the platen |49 so that inkedtype impressions may be produced upon a page carried by platen |139.

The platen |49 is rotatably supported by the opposed ends of a carriage23S. The carriage is Asupported for movement transversely of the typmgunit by rails, ci'ie cf which is indicated as u1, secured to the rearcasting member 64. The

casting 64 also supports near the top thereof a bracket 238 which has athreaded aperture in coaxial relation to the platen |49. A bushing 239threadedly engages the aperture in bracket 238 and rotatably supports asquare rod 24| which enters platen |49 through one of the hubs thereinand passes through a square portion of a tube which extends from end toend of the platen |49. The square shaft 24| is of suflicient length thatit may extend into or through the square portion of the tube on theinterior of platen |49 in any position which carriage 236 may occupy inits travel back and forth upon its supporting rails. Square shaft 24|has secured thereto a crank 242 which may be rotated manually to impartrotation to square shaft 24| and, through its cooperation with thesquare portion of the tube into which it extends, rotation may beimparted to platen Carriage 236 also supports a paper guiding plate orbasket 243 which is disposed below the platen for guiding a page in theprinting position and which, in turn, supports pressure rolls 244 andpaper guide fingers 246. Carriage 236 may have associated therewithcharacter spacing mechanism and line feeding mechanism in accordancewith the disclosure of the copending application of Albert H. Reiber,Serial No. 77,796. A rotatable drum 241 is provided for housing acarriage return spring. A carriage return belt 248 has one end securedto the periphery of drum 241 and the other end secured to carriage 236.

Terminal blocks and slip connections are provided for connecting thevarious electrical circuit elements in the keyboard transmittermechanism and in the typing unit to external circuits. The referencenumeral 25| indicates a terminal block 40 which is mounted on thekeyboard base casting I8 behind the typing unit. Terminal block 25| hasterminals 252 individually engaged by slip connection tongues 253carried by a slip connection block 254. Slip connection block 254 is se-45 cured to the rear portion 62 of the primary typing unit casting belowthe secondary or carriage supporting casting 64. The contacts 252 andtongues 253 may form electrical connections between the electromagnet 68carried by the typing 50 unit and the transmitting contact springs 21carried by the keyboard base and between the selector magnet andexternal circuit. Thus-the secondary casting and all of the elementswhich it supports may be removed from the typing unit 55 withoutdisturbing the electrical connection between the selector magnet 68 andthe transmitting contacts and between the external circuit and both theselector magnet and the contacts. Also the entire typingunit may beremoved from 60 the keyboard base by removal of the thumb screws 63whereby the slip connection tongues 253 will be removed from engagementwith contacts 252 without disturbing the electrical connections betweenthe transmitting contacts and 65 external circuit.

The general operation of the typing or receiving unit hereinbeforedescribed is as follows: Permutation code signals impressed upon atelegraph line to which the receiving unit is connected en- 70 ter thereceiving unit at terminals 252 and slip connection 253 and areimpressed upon the selector magnet 68. Gear 18 and the shaft which itdrives, being in operation, selector assembly 61 which is frictiondriven is released for a cycle of operation by the start impulse of asignal combination ln accordance with the well-known practice employedin the operatlonof single-magnet selector mechanisms controlled bystart-stop sigt engages arm ||5 of bail ||6 and rocks the bail inclockwise direction whereby clutch throwout lever v||2 ,is withdrawnfrom restraining engagement with driven clutch' element |08, carried bythe front shaft, whereupon the driven element |08 is shifted intoengagement with driving element |01, and cam sleeve ||3 is set inoperation for a cycle comprising one revolution.

The first operation performed after cam sleeve |3 is set in operation isthe clockwise rocking of transfer bail 9|, by transfer cam ||9,operating through cam follower roller |22 and follower arm |23. Transferbail 9| operates to set the code discs contained in the code discselector mechanism 84 in correspondence with the setting of. the swordlevers. 'I'he shifting of the code discs to accomplish the selection ofa new stop pin 86 is accompanied by the camming of the previouslyselected stop pin into unselected position whereby the restraint upontype wheel stop arm 81 is removed and shaft 84 and type wheel |44 rotateto seek a new stop position. At this time, the type wheel |44 is held inits lowermost position ilifthe type wheel lifting bail |3| and bail armAs soon as the transfer has been accomplished, the selector cam barrel61 may be released for rotation to effect the setting of the swordlevers according to a new signal combination. The timing of theoperation of selector cam assembly 61 and of cam sleeve ||3 carried byfront shaft |03 is such, with respect to the speed of operation oftransmitting apparatus, in response toA which this receiving mechanismis intended to operate, that the transfer has been effected before theselector cam barrel is released by the start impulse of the next signalcombination.

A predetermined interval after the transfer operation has beenperformed, cam |25 begins to rock type wheel lifting bail |3| incounterclockwise direction and the type wheel |44 is elevated intoprinting position. The position in which the type wheel will be arrestedwill be determined by the position occupied by slide member 201. Bail|3| will, however, be rocked to extreme clockwise position regardless ofthe position in which type wheel |44 is arrested, spring |31 yielding topermit the motion of bail |3| to be completed.

A short angular distance before cam 25 has rocked bail |3| to extremecounterclockwise position, cam ||8, carried by cam sleeve ||3, engagesclutch throwout lever |28 of the clutch which comprises driving element|24 and driven element |29 on the main shaft or inner cam shaft, wherebythe main assembly |30 is set in operation. By the time cam |25 hasrocked type wheel lifting bail |3| to extreme counterclockwise position,internal cam |86, included in the main cam assembly |30, has assumedcontrol of its follower arm |81, which is carried by bail |3|, so thattype wheel lifting bail |3| is held in extreme counterclockwise positionafter cam |25 has come to rest and has relinquished control over bail|3|.

The front shaft may be rotated at the same speed as the main shaft sothat in the reception of signals continuously transmitted, the camsleeve 3, carried by the'front shaft |03, will have a rest periodbetween cycles of operationequal to the rest period of selector camassembly 61 between successive code' combinations. Cam sleeve ||3 may,therefore, begin its next cycle of rotation before the cam assembly |30,carried 'by the main or inner shaft, has completed much of its cycle ofoperation. While cam |86 is holding type wheel |44 elevated, and beforecam sleeve H3 can have rotated suiil'- ciently far in the next cycle tooperate the trans-` fer bail, the print cam |5| brings its sharp dropointo alignment with roller |52, carried by the print bail operatinglever |53, whereupon spring |58 rotates lever 53 sharply incounterclockwise direction and this movement is imparted to print bail|6|, which drives print hammer |69 into engagement with the selectedtype pallet and which overtravels sufiiciently to produce an impactbetween the selected type pallet and a message page carried by platen|49. At substantially the same time that print cam |5| permits printbail operating lever |53 to be rocked counterclock'wise by its spring|58, cam groove |91, in the upper surface of cam |5|, operates itsassociated bail |92, which tests for function selection as disclosed inthe copending application `of Albert Reiber, Serial No. 77,796. Theeiect of such testing is that a function bar |93,

` initiate or perform its function.

nfl

Since tension spring |66 is effective substantially instantaneouslyafter the printing of acharacter to withdraw print hammer |69 to itsretracted position, which operation can be performed much more rapidlyby spring |66 than` it could be by cam |5|, operating through bailoperating lever |53, the transfer of the next signal combination can beperformed sooner after the print operation than it could be withpositive printing and retraction of the print hammer. The sooner afterthe printing operation that the transfer of the next signal combinationmay be performed, the greater is the interval of time that may beallotted for rotation of the type wheel into a new stop positioncorresponding to the new selection and, therefore, the slower can be thespeed of rotation of the type wheel shaft 88. The maintenance of minimumrotational velocities consistent with efficient operation is desirablein order to minimize inertia effects.

Internal cam |86 is required -to hold type wheel |44 elevated only untilthe print operation has been performed. As cam |5| continues to ro` tateand restores print bail operating lever |53 to its extreme clockwiseposition,- cam |86 permits bail |3| and bail arm |34 to return toextreme clockwise position, the restoration not being abrupt nor violentbut rather being controlled and gradual.

As set forth in the description of apparatus, cam 202 operates functionbaill lever arm |99 t0 reciprocate the spacing pawl 206 and the functionbars |93. Immediately after the printing of a character has beenaccomplished, the carriage 236 may be spaced to bring a blank portion ofthe page into position to receive the next character. If instead of acharacter having been selected for printing a function has beenselected,

and the selection evidenced by the clockwise rocking of the particularfunction bar by operation of bail |92 substantially simultaneously withthe operation of print bail lever |53, the apparatus is conditioned forthe performance of the function. The operation of lever |99 by cam 202is gradual so that there is no abruptness in the performance of thefunction. As the func--- tion bars |93 are moved rearwardly of thetyping unit by operation of function lever |99, the one of the functionbars |93, which has previously been rocked into effective positioninitiates or performs the function such as shift, unshift, line feed,carriage return, and various other desirable functions as disclosed inthe copending application of Albert H. Reiber, Serial No. 77,796. Theoperation of function bail lever 99 is the last operation performed bythe cams on cam sleeve |24 before the cams return to rest position, atwhich point, clutch throwout lever |21 separates driven clutch element|29 from driving element |24.

From the foregoing it will be observed that during the reception ofisolated or widely separated signal combinations, there occurs a trainof operations for each signal combination which begins with the settingin rotation of selector cam cylinder 61 and which vends with thearrestment of main cam assembly |30.- The selector cam cylinderco/operates with the selector mechanism Ato'set up `the signalcombination received, trips off the cam sleeve H3 on "the vfront-shaft,and comes to rest. The cams carried by sleeve H3 transfer the signalcombination lto the code disc selector, elevate the type Wheel toprinting position under the control of the shift and unshift slidemember 201, trip off the main cam assembly on the inner shaft, and cometo rest. The c-ams on the main cam sleeve effect the operation of printhammer |69,- test for the presence of a function selection, control thelowering of the type wheel to its idle position, effect characterspacing and the performance of any function selected, and come to rest.

When, however, signal combinations are being received at substantiallymaximum frequency, as is the case when the transmitter from which thesignals are being received is operated by a perforated tape, or if it isa keyboard transmitter, being operated by a skillful operator, the stoptime between cycles of operation of selector cam assembly 61 will bevery brief. The stop time between successive cycles of the front cam ||3and the main cam cylinder |30 will be correspondingly brief, butdefinite phase relationships between all of the cam assemblies will bemaintained. Thus, all of the cam assemblies may be rotatingsimultaneously, and no two of them may be at rest at the same time.However, the operations which they control will proceed in orderly`fashion exactly in accordance with the planned timing of the receivingmechanism. Any signal combination introduced at thevselector magnet 68,whether relating to the printing of a character or to the performance ofa funcjtion, will have become effective for the purpose for which it wasintroduced before the completion of the operation initiated by theselector cam assembly 61, and there will be no storage of a signalcombination requiring an additional cycle of operation of the selectorcam barrel for its clearing out, as is the case in some printingtelegraph mechanisms, in which the transfer and printing operations arenot assigned to be performed Aby cams included in separate cam assof'semblies, but are performed by cams included in a single cam assembly,and in which there isinsuiiicient time between the transfer operationand the end of the cycle of the single cam assembly for the completionof rotation of the type wheel, or other conditioning of the printingelement and the actual printing operation. In some printing telegraphreceiving apparatus having a single operating cam assembly, such forexample, as that exemplified in the copending application Serial No.77,796, the printing operation is timed to precede the transferoperation in each cycle of the cam assembly so that the printingoperation always lags one cam cycle behind the transfer operation, andat the completion of any message, the signal combination for the lastcharacter or function remains in storage in the code disc selectormechanism and necessitates the introduction of an idle cycle of theselector cam assembly for its clearing out. In the printing Itelegraphreceiver mechanism according to the present invention, the printingoperation and also the operation of the function mechanism follows thetransfer operation in the general cycle of operation of the mechanismwhich may be considered as beginning with the starting of the selectorcam assembly 61 into rotation and terminating with the arrestment of thecam assembly |30 carried by the main or inner operating shaft. It willthus be apparent that the printer always 'clears out and prints inaccordance with the last signal combination received and no signalcombination is ever left in storage in the selector mechanism.

In the foregoing general description of -the printing telegraphapparatus, in accordance with the invention, certain details were notdescribed because the description was restricted to Fig. 1 in whichthose details could not be clearly shown. 40 They are, however, shown inFigs. 2 and 3 and will now be described, having reference particularlyto the detailed showings.

Type wheel |44 comprises upper ring element 26| and lower ring element2612 joined by a web 45 portion which has radial slots in which typepallets |19 are slidable. As indicated in Fig. 2, the type pallets arerecessed, recesses in those of each row opening toward the recesses ofthose in the other row, and seated in the recesses of all of 50 the typepallets |19 in a row is a garter spring 263 which bia-ses all the typepallets it engages to their innermost position. The lower ring 262 oftype wheel |44 has a cylindrical upset portion 264, the upset portionbeing coaxial with the type 55 Wheel.

The upset portion 264 of the type wheel |44 rests on the top of a hub266 which is slidable upon type wheel shaft 88. At one point in the'periphery of type wheel hub 2616, there is a notch or recess 261 whichreceives a pin 268 secured to and depending from the upset portion 264of type wheel |44. A plurality of clamping screws 269 are employed forrigidly Isecuring type wheel |44 to hub 266.

Hub 266 is supported by type wheel lifting frame |39, and to this endhub 266 is grooved as at 21| to provide a portion of reduced diameterbetween flanges or shoulders. Intermediate the apertures through whichextend the guide pins or screws |46, top portion |43 of frame |39 isprovided with a recess which extends inwardly from the foremost edgesthereof. This recess is of such width that its defining edges enter thegroove 21| and substantially engage the reduced 75 portion of the hub,thereby being disposed beaaa-1,546

tween the spaced shoulders. The recess in frame |39 which is entered bythe reducedI portion of hub 266 need have no enclosure to assure theretention of the hub, as the location of the type wheel shaft isestablished and the position of frame |39 is definitely established bypins |46. From the foregoing, it will be apparent that hub 266, whilebeing slidable upon shaft 88, is secured to type wheel shifting frame|39 and, in turn, has secured to it type wheel |44. Thus, any motionwhich frame |39 undergoes is imparted to type wheel |44.

Hub 266 has secured thereto, by means of clamping nut 212, aradiallyextending arm 213 at the free end of which is a depending arm214. Type wheel shaft 88 has secured thereto, by means of clamping screw216, a split bushing 211. Bushing 211 has integral therewith a radiallyextending arm 218, the free end of which is slotted to receive dependingarm 214 of type wheel hub arm 213. Rotation is imparted from shaft 88 tohub 266 by means of arm 218 of split bushing 211 through the engagementwith depending arm 214 of radial arm 213 of hub 266. Arm 214 of hub arm213 fits freely into the slot in driving arm 218 so that When hub 266 islifted by frame |39, arm 214 may slide in the slot in arm 218 and thusrotation may be imparted by shaft 88 to type wheel |44 while the typewheel is in motion upwardly or downwardly under the control of frame |39or while the type wheel is being held in any predetermined horizontalplane.

Pin 268 carried by type wheel |44, cooperating with slot or recess 261in hub 266 enables the fitting of a type wheel to hub 266 and thereforeto shaft 88 in the correct angular position with respect thereto, sothat type wheels may be interchanged without adjustment or the checkingof alignment. When a type wheel has been removed from hub 266 forrepairs or adjustment, the removal being accomplished by removal of theclamping screws 269, the type wheel may be restored to the properposition by fitting it to hub 266 with pin 268 entering slot 261, whichis the only position in which it will seat upon the hub, and byinserting and tightening the clamping screws 268. In substituting a newtype wheel, the only thing that need be known about it is that thearrangement of type elements around the periphery corresponds to theselective notching of the code discs contained in the code disc selectormechanism 84. If the type wheel is properly related to the code discselector mechanism, it Will assemble to hub 266 through the cooperationof slot 261 and pin 268 in position to print correctly in response tosignal combinations.

Although specic embodiments of the features of invention have beendisclosed and described herein, it will be understood that the inventionis not limited to such specific embodiments but is capable ofmodification, reorganization, Vrearrangement, and substitution of partsand elements without departing from the spirit of the invention andWithin the scope of the appended from said base plate and adapted toenter the slot in said hub for orienting said type carrier with respectto said hub, and means disposed v Within the space defined by the innerends of said type elements and accessible through the opening at the topof said annular type carrier I for removably securing the base plate ofsaid type carrier to said hub.

, HERMANIDTI'ERMANN.

